Control apparatus



Nov. 14, 1939. E D. RANEY ET AL 2,180,067

CONTROL APPARATUS Filed Sept. 21, 1937 2 Sheets-Sheet l 2% 0 #84 a ZZ 76 86 3 y l mg //5 I 55 34 4a /02 L I I INVENTOR Nov. 14, 1939.

Filed Sept. 21, 1937 E. D. RANEY ET AL CONTROL APPARATUS 2 Sheets-Sheet 2 vvvv Patented Nov. 14, 1939 UNITED STATES PATENT OFFICE CONTROL APPARATUS Application September 21, 1937, Serial No. 164,910

15 Claims.

In a control system, for example for a fuel burning device, it is desirable to delay the restarting of the device for a period of time after cessation of operation of the device in order to permit purging of gas from the furnace.

One of the objects of the present invention is to provide a control system, for example for a fuel burning device, in which upon cessation of operation, a control circuit is rendered inoperative, for a timed period, and therefore cannot operate to restart the system during this timed period although there is a demand for operation of the device.

Such Systems are of necessity provided with safety mechanism. which prevents'the ingress of fuel into the furnace in the event 'of abnormal conditions such as the failure of combustion at the time or starting or after the fuel burning device has been operating. Usually an electrically heated safety mechanism is employed in the system and it is desirable to maintain the mechanism heated during the entire operation of the burning device so that the same is efiective immediately for rendering the device inoperative in the event of an abnormal condition. It is also desirable to interrupt the ignition after a timed period so that ignition is furnished during a starting period only.

It is another object of the invention to utilize the timer of the safety mechanism to control the ignition also and to also utilize this timer for delaying the restarting of the burning device,

. for a timed period, after cessation of operation of the device.

In carrying out the foregoing object, it is a further object to provide a control system in which the control circuit, which is rendered inoperative upon cessation of operation of the burning device, is not rendered effective until the ignition circuit is rendered effective.

A still further object is to provide a control system in which the electrically operated heater is in the control circuit and which control circuit is rendered inoperative upon cessation of ,operation of the burning device.

Further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein preferred forms of embodiments of the present invention are clearly shown.

In the drawings:

Fig. 1 is a wiring diagram of one form of control system, the system being shown in the operating position, with the room thermostat in the cold or closed circuit position;

Fig. 2 is a view of the thermostat showing the same in its intermediate position;

Fig. 3 is a view similar to Fig. 2 showing the thermostat in the heated or open circuit position, and,

Fig. 4' is a wiring-diagram of another form of control system, the system being shown in the operating position.

Referring to Fig. 1, the system is illustrated as controlling the operation of a conventional type of oil burning device. The system, as shown, is operatively responsive to a thermostat 20, such as a room thermostat, which closes a low voltage secondary circuit when there is a demand for heat, to cause the oil burning device to operate, and which opens the secondary circuit when that demand is satisfied. A transformer relay 24 is utilized as a means to supply low voltage current to the system and as a means for operating various control switches. The secondary or starting circuit may be traced as follows: secondary coil 22 of transformer relay 24, wire 26, wire 28, contacts 30 and 32 and member 34 of thermostat 20, wire 36, resilient member 38, contacts and 42 of time relay switch 44, heating coil46 and wire 48. Completion of the secondary circuit, by room thermostat 20, causes the transformer relay 24 to draw its armature 50 upwardly to close the associated switches 52 and p 54. Closure of switch 54 energizes the motor and ignition circuits, which will be explained in detail hereinafter. Closure of switch 82 completes a shunt circuit around contact 30 of the thermostat 20. This circuit may be traced from secondary coil 22, wire 25, switch 52, wire 56, thermostatic metal 58, contactsifl, 32 and member 34 of thermostat 20, wire 36, resilient member '38, time delay switch 44, heating coil 46, and wire 48.

1 Thus it will be seen, that in order to start the system, the thermostat 20 must be in the position shown in Fig. 1, wherein all three contacts are in engagement. After closure of the holding switch 52, the thermostat may deflect to the position shown in Fig. 2, wherein the contacts 32 and 60 are in engagement and the circuit through contact 30 has been interrupted. This type of thermostat is well known in the art. Thesystem will remain operative until the thermostat '20 is heatedsuificiently to deflect to the position shown in Fig. 3, wherein all of the contacts of the thermostat 20 are separated, at which instant the secondary circuit is deenergized to cause the transformer relay 24 to release the armature 50.

The high voltage primary circuit includes the primary coil 62 of transformer relay 24, which is connected across the main line through a safety switch 64. The primary coil 62 is constantly energized while the safety switch 64 is in the closed circuit position. This circuit may be traced as follows: wire 66, to the primary coil 62, wire 68, safety switch 64, and wire I6. It will be noted that wires 66 and I6 connect to the line or current supply for the system.

The motor and ignition circuits for controlling the motor I2 and ignition device I4 are controlled by switch 54. The motor circuit may be traced as follows: wires 66 and I6, motor I2, wire 86, switch 54, wires 84 and 66, safety switch 64 and wire I6. The ignition circuit follows, wires 66, I6 and I8, ignition switch 66, wire 62, ignition transformer primary I4, wires 86 and 66, switch 54, wires 84 and 68, safety switch 64 and wire Ill. The ignition secondary circuit is shown at 89. It will be. noted that the motor I2 and ignition primary I4 are connected in parallel and upon initiation of operation are responsive to the operation of switch 54 controlled by the transformer relay 24. The ignition primary I4 is subsequently deenergized by the opening of the ignition switch 86.

The motor 12, previously mentioned, is used to propel a fuel pump and an air pump, to supply fuel to the fuel burning device, which fuel is ignited by the ignition device.

The normal operation of the system may be explained as follows: when the thermostat calls for heat, the secondary circuit of the system is energized, to cause the transformer relay to attract its armature 56 and close switches 62 and 54. Closure of switch 54 energizes motor I2 to cause fuel to be fed to the fuel burning device which fuel is ignited by the ignition device. Completion of the secondary control circuit also causes current to flow continuously through the heating coil 46 throughout operating periods of the fuel burning device. Col] 46 is disposed in intimate heat transfer relation to a U shaped bimetal thermostat 96 to cause the same to be deflected upwardly during the heating thereof. A shouldered pin 92, is disposed on the moving blade of the thermostat 96, the shoulder 94 of pin 92 being adapted to engage a pivotally mounted lever 96, which controls the ignition switch 86. After a predetermined period of heating of the thermostat 96, the same moves upwardly sufficiently to cause the shoulder 94 of pin 92 to engage the lever 96 and thus open the ignition switch 86. In this manner the ignition device is rendered inoperative, after a timed period of operation thereof. It is apparent that this operating period can be regulated to any period desired by moving lever 96 closer or farther away from the shoulder 94. of the pin 92 abuts a second pivotally mounted lever 98. A combustion responsive control I66 is provided and is disposed to operate a latch I62 between stops I64 and I66, through a conventional slip clutch. Thus when the combustion chamber is cold the latch I62 is positioned against stop I64 but after combustion is established, the latch I 62 is displaced by control I66 to engage stop I66. In this latter position the latch I62 will act as a stop for lever 96 when the same is moved upwardly a sufficient distance by deflection of bimetal 96. This effectively prevents further upward movement of the lever 96 and also prevents further upward deflection of the bimetal 96.

The moving end of the bimetal 96 is di The upper end to abut an' operating lever I66 on the safety switch 64 and in the abutting position maintains the safety switch 64 in closed circuit position. Suitable means, such as a spring II 6, are provided to bias the lever I66 to open circuit position of theswitch 64 when the lever I69 is released by the bimetallic strip 96. It will be noted that the aforementioned action of combustion control I66 through latch I62 prevents the bimetal 96 from deflecting upwardly sufliciently to release the lever I68 and thus, when combustion is established within the system, the safety switch 64 is maintained closed.

During the upward deflection of bimetal 96 the contacts 46 and 42 of time delay switch 44 aremaintained in engagement with each other due to the following action of the spring contact member 38, which carries the contact 46 and which is biased upwardly to cause the aforementioned following action.

Upon deenergization of the system due to opening of the thermostat 26, the secondary circult of the transformer relay 24 is deenergized to cause armature 56 to drop downwardly. A pin or rod II2 depends from the armature 66 and'is disposed to engage the resilient contact member 66, when the armature 66 drops downwardly, to depress the member 36 downwardly until the .66 when the same drops downwardly to maintain the bimetal 96 in engagement with safety switch lever I66. This is necessary since the combustion control acts quite rapidly due to the slip clutch connection and displaces latch I62 so that the same does not engage lever 96 prior to the time the bimetal 96 has cooled sufliciently to assure that it will not release the safety switch lever I66. Thus the armature 66 maintains the safety switch closed upon deenergization of the system and after the combustion control has cooled.

'When' combustion is not established within the system, upon initial starting thereof, the combustion control I66 is non-operative and therefore bimetal 96 is permitted to deflect sufficiently to release safety switch lever I66 which opens switch 64 and deenergizes the system. A similar action occurs upon failure of combustion during the operating cycle of the system, wherein the control I66 displaces latch I62 out or engagement with lever 96 to allow bimetal 96, which is heated by coil 46 to a temperature above the temperature necessary to release the lever I66, to move upwardly for causing thesafety switch to be instantly open circuited. In either of the above mentioned exigencies, the safety switch must be reset manually before the system can be restarted.

time delay switch 44, the ignition switch 66 is J reclosed to assure that the ignition device I4 will be in readiness to operate when the system is reenergized. This delay of restarting is timed, through thermostat 80, so that suflicient time elapses to permit purging of the furnace of gas and thereby insures against explosives.

Referring to Fig. 4, a similar system is shown with the exception that a two wire thermostat In is utilized in place of the three wire thermostat 20. In this system, the holding switch 52 can be eliminated and the secondary circuit may be traced as follows: secondary 22, wire 26, contacts I22, I24 and bimetal I26 of the thermostat I20, wire 38, resilient member 38, time delay switch 44, heating coil 46 and wire 48. The operation of apparatus in this system is identical in every respect to the operation of the apparatus as previously described in connection with Fig. 1.

It is apparent that certain advantages are present. Quick operation of the safety mechanism is insured because the heating coil therefor is continuously energized during the operation of the fuel burning device. In the event of combustion failure, the thermostat immediately will open the safety switch 64 as soon as the combustion control releases lever 98. To have the heater 46 operate continuously during the operation of the burning device necessitates a continuously energized circuit therefor and in the event of temporary power failure, the circuit for the heater coil must be reenergized upon return of the electrical power, in order to insure the safety operation of the system. By the present invention, safe operation is insured under all conditions. The heater 46 for the safety mechanism is in series with the starting circuit and the arrangement is such that the starting circuit cannot be reenergized for a timed period after cessation of operation of the burning device. Also the ignition circuit is rendered effective at before the starting circuit is energized. In this manner, the fuel supply motor 12 cannot be restarted until ignition is present and the furnace is purged of gas.

While the forms of embodiment of the present invention as herein disclosed constitutes preferred forms, it is to be understood that other forms might be adapted, all coming within the scope of the claims which follow:

We claim:

1. A control system for a fuel burning device comprising in combination; electrically operated means for controlling the fuel burning device; an

electrical circuit for rendering said means opera- 7 tive including a switch; means responsive to deenergization of the electrically operated means for opening said switch; and thermostatic means operable after a predetermined time for closing said switch.

2. A control system for a fuel burning device comprising in combination; electrically operated means for controlling the fuel burning device; an electrical circuit for rendering said means operative including a switch; means responsive to deenergization of the electrically operated means for opening said switch; and timing means operable after a predetermined time for closing said switch.

3. A control system for a fuel burning device comprising in combination; electrically operated means for controlling the fuel burning device; an electrical circuit for rendering said means operative including a switch; electrically operated thermostatic means; means for energizing the thermostatic means during operation of the fuel burning device; a safety switch actuated by the thermostatic means for rendering the circuit inoperative a predetermined time after energize.- tion of the circuit; means responsive to the establishment of combustion for preventing operation ofthe safety switch; and means responsive to deenergization of the electrically operated means for opening the first mentioned switch; said thermostatic means for reclosing said first mentioned switch a predetermined time after the opening thereof. 7

4. A control system for a fuel burning devic comprising in combination, electrically operated means for controlling the fuel burning device; an electrical circuit for rendering said means operative including a switch; electrically operated timing means; a safety switch actuated by the timing means for deenergizing the circuit a predetermined time after energization thereof; means responsive to the establishment of combustion for preventing operation of the safety switch; means responsive to deenergization of the electrical means for opening the first mentioned switch; said timing means being operable to reclose said first mentioned switch a predetermined time after the opening thereof.

5. A control system for a fuel burning device comprising, electrically operated means for causing starting of said device; an electric circuit for rendering said means operative; temperature responsive means adapted to be heated when the fuel burning device is started; a switch associated with said temperature responsive means and connected in said circuit, means for biasing said switch closed during the operating period of the fuel burning device; and means rendered effective upon deenergization of the eletrically operated means for opening the switch for causing said circuit to be non-operative, said temperature responsive means being operative to close the switch.

6. A control system for a fuel burning device comprising electrically operated means for causing starting of said device; an electrical circuit for rendering said means operative; an electrically heated thermostat adapted to be energized when the fuel burning device is started; a switch adapted to be operated by said thermostat and connected in said circuit; means for biasing said switch closed during the operating period of the fuel burning device; and means rendered effective upon deenergization of the electrically operated means for opening said switch for causing said circuit to be non-operative, said thermostat being operative to close the switch a predetermined time after deenergization of the thermostat.

7. A control system for a fuel burning device comprising, electrically operated means for causing starting of said device; an electrical circuit for rendering said means operative; an electrically heated thermostat adapted to be energized when the fuel burning device is started; a switch adapted to be operated by said thermostat and connected in said circuit; means for biasing said switch closed during the operating period of the fuel burning device; ignition means for igniting the fuel; a controller for the ignition means, said electrically'heated thermostat being adapted to actuate said controller subsequent to the starting of the fuel burning device and after a predetermined period of operation of the ignition means; and means rendered effective upon deenergization of the electrically operated means for opening said switch for causing said circuit to be nonoperative a said thermostat being operative to 75 close the switch a predetermined time after opening thereof.

8. A control system for a fuel burning device comprising, electrically operated means for causing starting of said device; an electrical circuit for rendering said means operative; an electrically heated thermostat adapted to be energized when the fuel burning device is started; a switch adapted to be opened by said thermostat and connected in said circuit; means for biasing said switch closed during the operating period of the fuel burning device; ignition means for igniting the fuel; a controller for the ignition means, said electrically heated thermostat being adapted to actuate said controller subsequent to the starting of the fuel burning device and after a predetermined period of operation of the ignition means; a safety switch operable to stop the fuel burning device and adapted to be actuated by the electrically heated thermostat subsequent to the operation of the ignition controller; means responsive to the establishment of combustion for preventing the safety switch from stopping the fuel burning device; and means rendered effective upon' deenergization of the electrically operated means for opening said first mentioned switch for causing said circuit to be non-operative until said thermostat operates to close the first mentioned switch.

9. A control system for a fuel burning device comprising, electrically operated means for causing the starting of said device; an electric circuit for rendering said means operative; a switch connected in said circuit; means for biasing said switch closed during the operating period of the fuel burning device; ignition means for igniting the fueli a switch for controlling the operation of the ignition means; an'electrically heated thermostat adapted to be energized when the fuel burning device is started and to be continuously heated during the operating period of the fuel burning device, said thermostat being adapted after a predetermined period of heating thereof to actuate said ignition switch; and means rendered effective upon deenergization of the electrically operated means for operating said flrst mentioned switch for causing said circuit to be non-operative; and means actuated by said thermostat during cooling thereof to close the first mentioned switch.

10. A control system for a fuel burning device comprising, electrically, operated means for causing the starting of said device; an electric circuit for rendering said means operative; a switch upon deenergization of the electrically operated means for opening said first mentioned switch,

connected in said circuit; means for biasing said switch closed during the operating period of the fuel burning device; ignition means, for igniting the fuel; a switch for controlling the operation of the ignition means; a safety switch for deenergizing the fuel burning device; an electrically heated thermostat adapted to be energized when the fuel burning device is started and continuously heated during operating periods of the fuel burning device; means interconnecting the thermostat and the three mentioned switches, said thermostat being adapted to successively open the ignition switch and the safety switch after a predetermined period of operation of the fuel burning device; means responsive to the establishment of combustion for preventing opening of the safety switch; and meansrendered eifective said mentioned switch being closed by the thermostat on cooling of the thermostat.

11. A control system for a fuel burning device comprising in combination, electrically operated means for controlling said fuel burning device;

a circuit for said means; a thermostatic device adapted to be electrically heated continuously 5 during operating periods of the fuel burningdevice, and in said circuit, and including a thermostatic contact member which is deflected by the heat; a following contact disposed to engage the thermostatic contact member during deflection 10 thereof; and means operated by the electrically operated means upon deenergization of the same for separating the following contact and the thermostatic contact member for interposing a delay between successive energizations of the electricall5 ly operated means.

12. A control system for a fuel burning device comprising in combination; electrically operated means for controlling said fuel burning device; a

circuit for said means; ignition means for ignit- 20 ing the fuel; an ignition switch for controlling the operation of the ignition means; a thermostatic device adapted to be electrically heated during operating periods of the fuel burning device and in said circuit, including a thermostatic 25 contact member which is deflected by the heat; a resiliently mounted contact disposed to follow the movement of the thermostatic contact memher. said thermostatic contact member being adapted to open said ignition switch after a pre- 30 determined period of heating of the thermostatic member; and means operated by the electrically operated means upon deenergization of the same for separating said resiliently mounted contact and said thermostatic contact member for inter- 3 posing a delay between successive energizations of the fuel burning device. n

13. A control system for a fuel burning device comprising in combination, electrically operated means for controlling said fuel burning device; a 40 circuit for said means; ignition means for igniting the fuel; an ignition switch for controlling the operation of the ignition means; a safety switch operable to denergize the electrically operated means; a thermostatic switch device in said circuit and adapted to be electrically heated during operating periods of the fuel burning device, including a thermostatic contact member which is deflected by the heat; a resiliently mounted contact disposed to follow the movement of the thermostatic control member, said thermostatic switch device being adapted to actuate flrst said ignition switch and then said safety switch after a predetermined period of heating of the thermostatic member; means responsive to combustion for preventing the safety switch from deenergizing the electrically operated means;

and means operated by the electrically operated means upon deenergization of the same for sep-" arating said resiliently mounted contact and said thermostatic member for interposing a delay between successive energizations of the fuel burning device.

14. A control system for a fuel burning device comprising in combination, electrically operated means for controlling said fuel burning device; a control circuit for said electrically operated means; a thermostatically operated switch in series with said electrically operated means, said switch comprising a movable contact member and a thermostat adapted to actuate said contact,

\ and a second movable contact member; means for heating said thermostat in response to ener- U gization of said fuel burning device; means for biasing the second contact member against the first mentioned contact member; and means actuated in response to deenergization of said electrically operated means for biasing said second contact member to a position away from the first mentioned contact member.

15. In a control system for an electrically operated fuel burning device, a magnetically operated switch means for controlling said device; a circuit for controlling the operation of said magneticaily operated switch means, a switch in series with said magnetic means; means for opening said switch in response to deenergization of said magnetic means; and means for closing said switch within a predetermined time period after the deenergization of said fuel burning device.

ELDON D. RANEY. WARREN H. F. SCHMIEDING.

I CERTIFICATE OF CORRECTION. I Patent No. 2,180,067; November 11L, 1959.

ELDON D. RANEY, ET AL.

It is hereby certified that error appears in the printed specification of the ebove numbered patent requiring correction as follows: Page 1, second column, line 25,-for the w nord "relay" read --delay-; line 52, for "82" read -52-; page 5,-second column, line 75, claim'Y, strike out "a" before "said" and insert instead a. comma; and that the said Letters Patent should be read with this correction therein that the same may conform to the rec- 0rd of the case in the Patent Office.

Signed and sealed this 20th day of May, A. D. 19141.

iHenry Van Arsdale, Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. I Patent No. 2,180,067.' November 11L, 1959.

' ELDOND. RANEY, ET AL.

It is hereby certified that error appears in the printed specification of the shove numbered patent requiring correction as follows: Page 1, sec- 6nd column, l-ine 25,'for the word "relay" read "delay"; line 52, for "82" v read --52--; page 5, second column, line 75, claim'Y, strike out "a" before "said" and insert instead a comma; and thalt the said Letters Patent should be read with this correction therein that the same may conform to the rec- 0rd of the case in the Patent Office.

Signed and sealed this 20th day of May, A. D. 191 1.

liem'y Van Arsdale Acting Commissioner of Patents. 

